Department of Pediatrics, Amsterdam University Medical Center, Amsterdam, The Netherlands.
Department of Public Health and Primary Care, KU Leuven, Kortrijk, Belgium.
Clin Chim Acta. 2018 Nov;486:259-264. doi: 10.1016/j.cca.2018.08.021. Epub 2018 Aug 16.
Beta-trace protein (BTP) is a low molecular weight protein, produced mainly in the cerebrospinal fluid. It has been proposed as a marker for kidney function. Recently, a new method for GFR estimation using mean normal values to rescale GFR marker concentrations has been described for creatinine and cystatin C, two commonly used endogenous markers for kidney function. The aim of this study is to apply this approach to BTP in children.
We retrospectively analyzed serum concentrations of creatinine, cystatin C and BTP measured during inulin clearance tests in children. BTP was measured using a particle-enhanced immunonephelometric assay (Siemens Healthcare). A novel BTP-based eGFR equation was developed using published normal values for children: eGFR[ml/min/1.73m] = 107.3/BTP/Q with Q = 0.69. Performance of this equation was compared to the established creatinine-based full age spectrum equation FASage and the cystatin C-based FAScys equations as well as the BTP-based Benlamri equation in terms of bias, % prediction error and P and P accuracy rates.
322 inulin clearance tests were studied. Overall, our novel equation performed comparably to the creatinine-based FASage and the BTP-based Benlamri equations but was less accurate than FAScys (P: 79.2 vs 86.3%, p = .008). Combining markers significantly enhanced performance compared to the single marker equations, with the exception of FAScys.
Rescaled BTP concentrations are a simple method for estimating GFR in children. However, the additional value of BTP for the estimation of GFR compared to rescaled creatinine and cystatin C still remains to be demonstrated.
β-痕迹蛋白（BTP）是一种低分子量蛋白质，主要在脑脊液中产生。它已被提议作为肾功能的标志物。最近，一种使用平均正常数值重新缩放用于估算肾小球滤过率（GFR）的标记物浓度的新方法，已被用于肌酐和胱抑素 C 这两种常用的肾功能内源性标志物。本研究的目的是将这种方法应用于儿童的 BTP。
我们回顾性分析了儿童在使用菊粉清除试验时测量的血清肌酐、胱抑素 C 和 BTP 浓度。BTP 采用颗粒增强免疫比浊法（西门子医疗）进行测量。使用已发表的儿童正常值开发了一种新的基于 BTP 的 eGFR 方程：eGFR[ml/min/1.73m] = 107.3/BTP/Q，其中 Q = 0.69。与已建立的基于肌酐的全年龄谱方程 FASage 和基于胱抑素 C 的 FAScys 方程以及基于 Benlamri 的 BTP 方程相比，该方程的性能在偏差、%预测误差和 P 和 P 准确度方面进行了比较。
共研究了 322 次菊粉清除试验。总体而言，我们的新方程与基于肌酐的 FASage 方程和基于 BTP 的 Benlamri 方程相当，但不如基于胱抑素 C 的 FAScys 方程准确（P：79.2 对 86.3%，p = .008）。与单标记物方程相比，组合标记物显著提高了性能，但 FAScys 除外。
重新缩放的 BTP 浓度是一种简单的方法，可以用于估算儿童的 GFR。然而，与重新缩放的肌酐和胱抑素 C 相比，BTP 对 GFR 估算的额外价值仍有待证明。
